Theobald's victory in the Christmas Party Nights At Dundalk Stadium Race was the highlight of a treble for Kevin Manning at the all-weather venue.
Jim Bolger's 11-10 favourite danced almost every dance during the turf season, but had his limitations exposed at the top table in the Dewhurst and Racing Post Trophy.
His sights were lowered significantly and he took full advantage, hitting the front two furlongs from home before keeping the staying-on Noivo three-quarters of a length at bay.
Manning had to be at his strongest to get the Bolger-trained Mainicin (20-1) home in front in the Winter Series At Dundalk 2018 Handicap.
Carried blazed a trail but began to tread water well before the furlong pole and as the pack swooped, Mainicin stayed on best to deny Johann Bach by half a length.
Canford Art attracted market support prior to her introduction under Manning in the Irish Stallion Farms EBF Maiden over the minimum trip, and it was justified as Peter Fahey's filly accounted for It's All A Joke by a length and a quarter at odds of 4-1.
Zihba (15-8) was another to make a successful start to his career in the seven-furlong Irish Stallion Farms EBF Maiden.
The Fozzy Stack-trained Choisir colt holds an Irish 2,000 Guineas entry and while he has a long way to go justify it, he impressed in disposing of odds-on favourite Port Lions by a length and a quarter.
There were some old favourites in the Crowne Plaza Leading Jockey & Trainer Awards 2017 Handicap and it went the way of Beach Bar.
Richard O'Brien's gelding was allowed to go off at 20-1 after finishing down the field over a mile here a couple of weeks, but improved for dropping back a furlong and beat Geological by half a length.
Settle For Bay (100-30) completed a hat-trick in the Crowne Plaza Race & Stay Apprentice Rated Race, while 3-1 favourite Kirk's Dancer took the Christmas Party Nights At Dundalk Stadium Maiden.